Pathway candidateNCBI-verifiedprotein-coding

MTR

5-methyltetrahydrofolate-homocysteine methyltransferase

NCBI Gene: 4548 Ensembl GeneCards UniProt: Q99707

Pathway candidate — not linked to PFS or PSSD by any record here

MTR is in the library because it belongs to the methylation / one-carbon family. No study, report or commentary in the corpus names it, so a variant in MTR is not, by itself, evidence of anything related to post-drug syndromes.

Gene summary

A protein-coding gene on chromosome 1 (methylation and one-carbon metabolism). Encodes the 5-methyltetrahydrofolate-homocysteine methyltransferase. This enzyme, also known as cobalamin-dependent methionine synthase, catalyzes the final step in methionine biosynthesis.

Source: NCBI Gene, accessed 2026-10-07.

Protein reference (UniProt)

Protein: Methionine synthase
Function: Catalyzes the transfer of a methyl group from methylcob(III)alamin (MeCbl) to homocysteine, yielding enzyme-bound cob(I)alamin and methionine in the cytosol. MeCbl is an active form of cobalamin (vitamin B12) used as a cofactor for methionine biosynthesis. Cob(I)alamin form is regenerated to MeCbl by a transfer of a methyl group from 5-methyltetrahydrofolate. The processing of cobalamin in the cytosol occurs in a multiprotein complex composed of at least MMACHC, MMADHC, MTRR (methionine synthase reductase) and MTR which may contribute to shuttle safely and efficiently cobalamin towards MTR in order to produce methionine.
Pathway: Amino-acid biosynthesis; L-methionine biosynthesis via de novo pathway; L-methionine from L-homocysteine (MetH route): step 1/1.
Subcellular location: Cytoplasm.
Tissue specificity: Widely expressed. Expressed at the highest levels in pancreas, heart, brain, skeletal muscle and placenta. Expressed at lower levels in lung, liver and kidney.
Associated conditions: Homocystinuria-megaloblastic anemia, cblG type (HMAG); Neural tube defects, folate-sensitive (NTDFS).

Source: UniProtKB/Swiss-Prot Q99707, release 2026_03, licensed CC BY 4.0. This is the protein’s normal biology, not evidence about post-drug syndromes; associated conditions are inherited disorders of the gene, not PFS, PSSD or PRSD.

Why its pathway is in the library

One-carbon metabolism supplies methyl groups for DNA/histone methylation — the epigenetic layer implicated in persistent post-drug changes.

Written for the whole methylation / one-carbon family, not for MTR specifically.

Mentioned in 0 corpus records

No corpus record names MTR directly yet. It is in the library because it sits in a pathway the corpus tracks (Methylation / one-carbon).

Also in methylation and one-carbon metabolism

All 5 genes

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Gene summary

Source: NCBI Gene, accessed 2026-10-07.

Protein reference (UniProt)

Protein: Methionine synthase
Function: Catalyzes the transfer of a methyl group from methylcob(III)alamin (MeCbl) to homocysteine, yielding enzyme-bound cob(I)alamin and methionine in the cytosol. MeCbl is an active form of cobalamin (vitamin B12) used as a cofactor for methionine biosynthesis. Cob(I)alamin form is regenerated to MeCbl by a transfer of a methyl group from 5-methyltetrahydrofolate. The processing of cobalamin in the cytosol occurs in a multiprotein complex composed of at least MMACHC, MMADHC, MTRR (methionine synthase reductase) and MTR which may contribute to shuttle safely and efficiently cobalamin towards MTR in order to produce methionine.
Pathway: Amino-acid biosynthesis; L-methionine biosynthesis via de novo pathway; L-methionine from L-homocysteine (MetH route): step 1/1.
Subcellular location: Cytoplasm.
Tissue specificity: Widely expressed. Expressed at the highest levels in pancreas, heart, brain, skeletal muscle and placenta. Expressed at lower levels in lung, liver and kidney.
Associated conditions: Homocystinuria-megaloblastic anemia, cblG type (HMAG); Neural tube defects, folate-sensitive (NTDFS).